Abstract: A buoyancy device to be clamped around least one longitudinal element. The buoyancy device comprises an assembled clamping device which is to be fastened around the element, and at least one buoyancy member connected to the clamping device. The buoyancy member is divided longitudinally in at least two sections and is arranged around the element together with the clamping device. The buoyancy member is divided in at least two separate or jointly pivoted buoyancy segments which may be folded around the elements(s) and loosely enclose a part of this (these). The clamping device is divided in at least two separate, or hinged together, clamping segments, adapted to be folded around the element(s), preferably in a firm and prestressed manner.